/*
 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <debug.h>
#include <io_driver.h>
#include <io_dummy.h>
#include <io_storage.h>
#include <string.h>

struct file_state {
    int in_use;
    size_t size;
};

static struct file_state current_file = {0};

/* Identify the device type as dummy */
static io_type_t device_type_dummy(void)
{
    return IO_TYPE_DUMMY;
}

/* Dummy device functions */
static int dummy_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info);
static int dummy_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
                 io_entity_t *entity);
static int dummy_block_len(io_entity_t *entity, size_t *length);
static int dummy_block_read(io_entity_t *entity, uintptr_t buffer,
                 size_t length, size_t *length_read);
static int dummy_block_close(io_entity_t *entity);
static int dummy_dev_close(io_dev_info_t *dev_info);


static const io_dev_connector_t dummy_dev_connector = {
    .dev_open = dummy_dev_open
};


static const io_dev_funcs_t dummy_dev_funcs = {
    .type = device_type_dummy,
    .open = dummy_block_open,
    .seek = NULL,
    .size = dummy_block_len,
    .read = dummy_block_read,
    .write = NULL,
    .close = dummy_block_close,
    .dev_init = NULL,
    .dev_close = dummy_dev_close,
};


static const io_dev_info_t dummy_dev_info = {
    .funcs = &dummy_dev_funcs,
    .info = (uintptr_t)NULL
};


/* Open a connection to the dummy device */
static int dummy_dev_open(const uintptr_t dev_spec __attribute__((unused)),
               io_dev_info_t **dev_info)
{
    assert(dev_info != NULL);
    *dev_info = (io_dev_info_t *)&dummy_dev_info;

    return 0;
}


/* Close a connection to the dummy device */
static int dummy_dev_close(io_dev_info_t *dev_info)
{
    return 0;
}


/* Open a file on the dummy device */
static int dummy_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
                 io_entity_t *entity)
{
    int result;
    const io_block_spec_t *block_spec = (io_block_spec_t *)spec;

    if (current_file.in_use == 0) {
        assert(block_spec != NULL);
        assert(entity != NULL);

        current_file.in_use = 1;
        current_file.size = block_spec->length;
        entity->info = (uintptr_t)&current_file;
        result = 0;
    } else {
        WARN("A Dummy device is already active. Close first.\n");
        result = -ENOMEM;
    }

    return result;
}


/* Return the size of a file on the dummy device */
static int dummy_block_len(io_entity_t *entity, size_t *length)
{
    assert(entity != NULL);
    assert(length != NULL);

    *length =  ((struct file_state *)entity->info)->size;

    return 0;
}


/* Read data from a file on the dummy device */
static int dummy_block_read(io_entity_t *entity, uintptr_t buffer,
                 size_t length, size_t *length_read)
{
    assert(length_read != NULL);

    *length_read = length;

    return 0;
}


/* Close a file on the dummy device */
static int dummy_block_close(io_entity_t *entity)
{
    assert(entity != NULL);

    entity->info = 0;
    current_file.in_use = 0;

    return 0;
}


/* Exported functions */

/* Register the dummy driver with the IO abstraction */
int register_io_dev_dummy(const io_dev_connector_t **dev_con)
{
    int result;

    assert(dev_con != NULL);

    result = io_register_device(&dummy_dev_info);
    if (result == 0)
        *dev_con = &dummy_dev_connector;

    return result;
}
